Help - how to save changes for network setups?

Hi,

This question is on how to save the setups made by ethtool on Red Hat
Linux. Here are what I did:

(1) Used the following command to set up NIC0:

"ethtool -s eth0 speed 100 duplex half autoneg off"

(2) The output of "ethtool eth0" shows:

Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Half

This mean command in first step is successful. However, after reboot,
the output of "ethtool eth0" shows:

Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full

It seems the previous setup was not saved. Could some one please tell
me how to save the setups made by ethtool?

Thanks,
BJ
--